Method of brazing metals.



JOHN A. RENNIE, OF NEIV YORK, N. Y;

METHOD OF BRAZING METALS.

Specification of Letters Patent.

Patented Dec. 11, 1906.

application filed March 20, 1906. Serial No. 306.965-

To all whom it nmy concern: Be it known that I, JOHN A. RENNIE, acitizen of the United States, residing at New York, in the county of NewYork and State of New York, have invented certain new and usefulImprovements in Methods of Brazing Metals, of which the following is aspecification, such as will enable those skilled in the art to which itappertains to make and use the same. I

This invention relates to thebrazing of I metals, and by means of myprocess,I am

enabled to braze together separate parts of metals, such as cast-ironsteel, or wroughtiron, such parts being of the same metal as cast-ironto cast-iron, or such parts being of different metals, such aswrought-iron to steel, or any other combination of theabovereferredtometals. To accomplish this obj ect, I prepare and apply acompound which consists of the following ingredients, combined in theproportions stated: oxid of manganese, powdered, two parts, by weight;'red hematite ore, powdered, three parts, by weight; boracic acid, dustform, two parts, by weight. These ingredients are to be thoroughlymingled by agitation, and sufficient Water is added to this mixture tomake a plastic paste. This mixture is applied cold to the surfaces ofthe joint of the metals to be joined together, and the joint thusprepared is brought to a cherrv-red heat in a furnace, to which heat isapplied in-any of the" wellknown forms, be it in a gas, coke, electric,or any other furnace usually employed for brazing purposes. When acherry -red heat color has beenattained, a flux, such as boracic acid,is applied to the jointure, and this is fol lowed by a separateapplication of spelter to the joint to be brazed, with the effect thatthe boracic-acid flux in entering the joint tends to remove all theloose metal particles of the joint by (lllV'lIlg or washing the same tothe exterior and is followed by the spelter, I

which enters into the joint thus cleaned and after assuming thefluidstate by means of the necessary melting heat will incorporate itselfwith the adjoining surfaces of the two umetals to be brazed and willfill out the interstices thus prepared.

In the foregoing described method of brazing the functions of theingredients forming the brazing compound are as follows: The oXid ofmanganese, which is in the anhydrate form, together with the redhematite ore chemically unite with such carbon in the cast-iron as issituated on and near thesurfaces of the abutting ends of the same. Theboracic acid in the powdered form in the compound is for the purpose ofacting as a flux to the oxid of manganese,the red hematite ore, and thecarbon, which latter is to be withdrawn from the abutting surfaces. Theapplication of the cherry-red heat to this brazing compound produces thedesired decarbonization by virtually withdrawing the carbon from thecast-iron and leaving the surface, microscopically considered, .in aslight porous state. Boracic acid added thereto removes or washes awaythe remnants of the compound in its chemically- 'I claim as new, anddesire to secure by Letters Patent, is

1. The herein-described process of brazing metals which consists indecarbonizing the abutting surfaces by the application of a compoundpaste consisting of oxid of manganese, red hematite ore and boracic acidin dust form, fusing the compound, adding spelter and melting the same.

2. The herein-described )rocess of brazing metals which consists in(ecarbonizing the abutting surfaces by the application of a compoundpaste consisting of the oxid of manganese, red hematite ore and boracicacid in dust form, fusing the compound, adding boracic acid to the cleanand decarbonized abutting surfaces, heating the parts and adding spelterand melting the same.

In testimony that I claim the foregoing as my invention 1 have signed myname, in presence of the subscribing witnesses, this 19th day of March,1906.

JOHN A. RENNIE.

itnesscs F. A. STEWART, C. E. hIULREANY,

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